The present disclosure relates generally to systems and methods for recycling lead-acid batteries, and more specifically, relates to purifying and recycling the lead content from lead-acid batteries.
The lead present in a lead-acid battery may be in a number of forms. For example, a lead-acid battery may include grids that contain lead alloys and lead oxide (PbO, PbO2), battery paste that contains metallic lead sponge, lead oxide, red lead, and/or lead sulfate, and posts and/or interconnects that contain metallic lead, lead alloys, and which may also contain non-lead alloys. While it may be desirable to attempt to recover lead from spent or retired lead-acid batteries, this material may include a variety of lead compounds (lead alloys, oxides, sulfates and carbonates) and an array of physical and/or chemical impurities. Existing methods for purifying lead typically rely almost entirely on multi-stage pyrometallurgical smelting in which some these compounds are combusted to produce volatile gases, some of which must be scrubbed (e.g., captured and removed from the exhaust stream) to prevent release, in accordance with environmental regulations, and subsequently the remaining impurities are removed from the metallic lead in various refining operations. Since these operations often require specialized equipment and certain consumables (e.g., solutions or other refining agents), this refinement process generally adds cost and complexity to the lead recovery process.